Asphalt Density Measurement System

Asphalt Density Measurement System

  • CoreLok IN103.1000

ASTM Standards D6752-02, AASHTO T-331 and D6857-03

  • Maximum Specific Density
  • Aggregate Specific Density
  • Porosity

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An innovative, non-nuclear method of determining SuperPave, Stone Matrix (SMA),and coarse mix asphalt air voids


CoreLok performs 5 standard lab tests:

  • Bulk Specific Density
  • Maximum Specific Density
  • Aggregate Specific Density
  • Porosity
  • % Asphalt Content

The CoreLok® is a system for sealing asphalt samples so that the sample densities may be measured by water displacement methods. Samples are automatically sealed in specially designed puncture resistant polymer bags. Densities measured with the Corelok® system are highly reproducible and accurate. The results are not dependent on material type or sample shape. The GravitySuite™ PC software package calculates and manages your data for ease of operation.


One Machine for All your Density Measurements of Asphalt and Aggregate.

ASTM D6752, ASTM D6857, ASTM D7063. A fundamental density measurement. It does not require empirical calibrations. An accurate method for Bulk Specific Density measurement.


Bulk Specific Density of Compacted samples 

Bulk Density Specification ASTM D6752 and AASHTO T-331

Specific density is the single most specified parameter in the construction industry. For open graded mixes (i.e. SMA and OGFC) and absorptive mixtures of asphalt, the Saturated Surface Dry (SSD) method is inaccurate. Water infiltration in and out of the sample produces a lower than actual measurement for sample volume, higher calculated density and a lower estimate of air voids. The CoreLok® system automatically seals these samples in specially designed polymer bag and allows for measurement of accurate water displacement test. The present sealing methods, Wax and films, are labor intensive and the results are extremely operator dependent. Click this link for the Bulk Density instructional video.


Maximum Specific Density (Gmm)

Max Specific Density Specification ASTM D6857 

This method may be used as an alternative to the conventional “Rice Test” for the determination of maximum specific density of loose asphalt mixtures. The CoreLok® test can be completed in seven minutes with minimal exposure to water, eliminating the need for a lengthy “Dry Back” method.


This procedure requires that a sample of dry asphalt mixture is placed inside the vacuum bags and sealed within the CoreLok® vacuum chamber. The bags are then cut open under water and a submerged weight is determined. The weight in air and the submerged weight can be used to calculate the maximum specific density of the asphalt mixture.


Apparent Specific Density, Absorption and Bulk Specific Density of Aggregates

AggPlus™ Specification ASTM D7370M

Oven dry aggregates are used in this test to determine the specific density and absorption of fine or coarse aggregates in less than 20 minutes. This test is highly accurate and repeatable.


In this test, a density measurement is obtained by fully saturating the sample with CoreLok® and another density is measured under an unsaturated condition. These two densities can be used with already known equations to calculate apparent specific Density, absorption and bulk specific Density. The AggSpec™ PC software allows for simple entry and calculation of these parameters.


Porosity of Compacted Asphalt Samples

ASTM D7063


Porosity is the measure of the percentage of water permeable voids in a compacted sample. Porosity gives an accurate estimate of sample permeability. You can now determine the interconnectivity of voids within your sample and determine your mix performance during design or after lay down. Two different mixes with 7% air voids can have different permeability performance on the field, depending on the interconnectivity of voids. However, these same mixes will never have the same porosity. For open graded mixes Porosity is a more meaningful measure of performance than % air voids. GravitySuite™ software included with CoreLok® provides automatic calculation of porosity based on a sealed and unsealed density of your sample.


Percent Asphalt Calculation

Use the CoreLok® to get an accurate measure of percent asphalt. The measurements using the CoreLok®, involves the determination of Density of combined aggregate, only available with the CoreLok® unit, and maximum Density of your mixture. These two critical measurements of your mixture can be used with the standard Superpave™ equations to accurately calculate the %AC in your mixture. This method is unique and very accurate for determination of %AC for difficult aggregates with significant variability and breakdown in the NCAT ignition furnace. The CoreLok® method is simple and can be completed in less than 20 minutes. 

Additional Specifications

Weight: 55kg / 121lbs

Height: 49.5cm / 19.5"

Foot Print: 48.9cm W x 63.6cm / 19.25" W x 25.0" D

Power: 120 VAC 13A (optional 220 VAC 6.5A)